Thread: Aluminium Ducting

Originally Posted by Gaza

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My clycone system I brought is around 30hp and over 1.5 in dia so a serious setup.
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Ok - then that is definitely well out of a home workshop league. BTW Do you mean 1.5 ft?

I Also think that in a home shop that bill penze setup external filtered is the way to go over small half arsed DC

I agree but unless the individual has lotsa spare$$ or is quite handy at building their own, then a half arsed DC that vents outside is the next best thing.

Originally Posted by BobL

Ok - then that is definitely well out of a home workshop league. BTW Do you mean 1.5 ft?

I agree but unless the individual has lotsa spare$$ or is quite handy at building their own, then a half arsed DC that vents outside is the next best thing.

See thread on cyclone here
https://www.woodworkforums.com/f200/b...system-138217/

Originally Posted by Gaza

See thread on cyclone here
https://www.woodworkforums.com/f200/b...system-138217/

That looks like a real beauty but definitely overkill for most weekend warriors.

This table from a noted US woodworking mag is interesting. The article found that extraction through metal piping was still excellent at 25ft or 8m!

Originally Posted by ShortPlank

The article found that extraction through metal piping was still excellent at 25ft or 8m!

I'm assuming that's straight, smooth bore metal ducting as apposed to ribbed flexible Al type ducting?

The ranking system seems a little narrow. Using 350cfm as a max performance indicator also seem too low and is probably more representative of fair/good/excellent chip sized dust extraction rather than the finer dust.

See attached table for CFM requirements from various institutes for woodworking dust extraction.

Originally Posted by ShortPlank

This table from a noted US woodworking mag is interesting. The article found that extraction through metal piping was still excellent at 25ft or 8m!

I agree with Gareth, 350 CFM is a factor of ~3 times too low for adequate fine dust collection. Bill Pentz site states over and over that a target rate of 1000 CFM volume collection at a speed of 4000 FPM is needed to achieve this.

This translates to using a 6.78" diam duct and that pipe MUST have as smooth a wall as possible. Metal ducting with spirals and welding seams will just add to the resistance and reduce bith volume and speed.

These guys seem to have a good and simple air duct calculator in Excel format.

You can quickly see the benefits of having straight ducting as apposed to flexi.